linux-kernel - [PATCH] gpiolib: of: fix lookup quirk for MIPS Lantiq

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Message-ID: <Zn8CZ47e3LFncrDP@google.com>
Date: Fri, 28 Jun 2024 11:35:19 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>
Cc: Martin Schiller <ms@....tdt.de>, Hauke Mehrtens <hauke@...ke-m.de>,
	Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] gpiolib: of: fix lookup quirk for MIPS Lantiq

As it turns out, there is a large number of out-of-tree DTSes (in
OpenWrt project) that used to specify incorrect (active high) polarity
for the Lantiq reset GPIO, so to keep compatibility while they are
being updated a quirk for force the polarity low is needed. Luckily
these old DTSes used nonstandard name for the property ("gpio-reset" vs
"reset-gpios") so the quirk will not hurt if there are any new devices
that need inverted polarity as they can specify the right polarity in
their DTS when using the standard "reset-gpios" property.

Additionally the condition to enable the translation from standard to
non-standard reset GPIO property name was inverted and the replacement
name for the property was not correct. Fix this as well.

Fixes: fbbbcd177a27 ("gpiolib: of: add quirk for locating reset lines with legacy bindings")
Fixes: 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API")
Reported-by: Martin Schiller <ms@....tdt.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---
 drivers/gpio/gpiolib-of.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 59c7f8a2431a..d21085830632 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -203,6 +203,16 @@ static void of_gpio_try_fixup_polarity(const struct device_node *np,
 		 */
 		{ "qi,lb60",		"rb-gpios",	true },
 #endif
+#if IS_ENABLED(CONFIG_PCI_LANTIQ)
+		/*
+		 * According to the PCI specification, the RST# pin is an
+		 * active-low signal. However, most of the device trees that
+		 * have been widely used for a long time incorrectly describe
+		 * reset GPIO as active-high, and were also using wrong name
+		 * for the property.
+		 */
+		{ "lantiq,pci-xway",	"gpio-reset",	false },
+#endif
 #if IS_ENABLED(CONFIG_TOUCHSCREEN_TSC2005)
 		/*
 		 * DTS for Nokia N900 incorrectly specified "active high"
@@ -512,9 +522,9 @@ static struct gpio_desc *of_find_gpio_rename(struct device_node *np,
 		{ "reset",	"reset-n-io",	"marvell,nfc-uart" },
 		{ "reset",	"reset-n-io",	"mrvl,nfc-uart" },
 #endif
-#if !IS_ENABLED(CONFIG_PCI_LANTIQ)
+#if IS_ENABLED(CONFIG_PCI_LANTIQ)
 		/* MIPS Lantiq PCI */
-		{ "reset",	"gpios-reset",	"lantiq,pci-xway" },
+		{ "reset",	"gpio-reset",	"lantiq,pci-xway" },
 #endif
 
 		/*
-- 
2.45.2.803.g4e1b14247a-goog


-- 
Dmitry